Deleting the active project leaves its draft marked saved #519

Deleting the active project from Project Info clears the Save target (handleMetadataProjectDeleted in ProjectModals.tsx) but leaves the draft's dirty flag alone. A clean draft then holds analysis that is saved nowhere, with no ● marker, so New or Open replaces it without asking.

To reproduce: open a project with analysis, leave it unedited, delete it from Project Info, then choose Open on another project. No confirmation appears.

Expected: the draft is marked unsaved once its project is deleted, unless it is empty.

Found while reviewing #512, whose book discard marks the draft unsaved when no project is active.